Grate magnet



1953 M. D. WOODRUFF 2,822,089

GRATE MAGNET Filed Dec. 28, 1949 Inventor mm WM United States Patent GRATE MAGNET Maurice D. Woodrulf, Springfield, Ohio, assignor to The Bfalaefii Bros. Company, Springfield, Ohio, a corporation 0 0 Application December 28, 1949, Serial No. 135,398

13 Claims. (Cl. 209-223) This invention relates to magnetic separators, and more particularly to those used to remove metal particles from grain, coffee, peanuts and the like, in a processing or handling step of such materials.

Heretofore these separators have been placed in the floor of a chute or like part of a conveying system in such wise that the grain or other material passes over the separator with entrained metal particles adhering to the separator and being deposited thereon. It is proposed by the instant invention to introduce a new conception in separating methods, wherein the material is constrained to pass through a grate type separator in close proximity to the magnets, which separator may be conveniently mounted in a hopper for gravity feed of the material to the magnet.

The object of the invention is to simplify the construction as well as the means and mode of operation of grate type separators as disclosed herein, whereby such separators may not only be economically manufactured, but will be more eflicient and satisfactory in use, adaptable to a wide variety of applications and be unlikely to get out of repair.

A further object of the invention, which is concerned with the grate magnet as a new article of manufacture, is to expose the flowing material more effectively to magnetic attraction.

Another object of the invention is to obtain effective magnetic attraction without imposing any material restriction to flow through the magnet.

A further object of the invention is to utilize a plurality of magnets, arranged in rows, to induce alternate polarity in intersecting members which, with the rows of magnets, make up the grate structure.

. Still another object of the invention is to obviate the possibility of metal particles failing to be. intercepted by the magnet because of descent midway between the intersecting members or pole pieces.

A still further object of the invention is to provide deflecting means in accordance with the preceding object without, however, restricting flow to and through the magnet.

A further object of the invention is to provide a separator possessing the advantageous structural features, the inherent meritorious characteristics and the mode of operation herein mentioned.

With the above primary and other incidental objects in view as will more fully appear in the specification, the invention intended to be protected by Letters Patent consists of the features of construction, the parts and combinations thereof, and the mode of operation, as hereinafter described or illustrated in the accompanying drawings, or their equivalents.

Referring to the accompanying drawing, wherein is found the preferred but obviously not necessarily the only form of embodiment of the invention,

Fig. 1 is a view of the magnet, with deflecting means, in top plan;

2,822,08 Patented Feb. 4, 1958 2 Fig. 2 is a view in side elevation, partly broken away, and

3 is a view in end elevation, partly broken away. L1ke parts are indicated by similar characters of reference throughout the several views.

Referring to the drawing, a separator in accordance with the instant invention has a grate-like construction,

it being adapted for installation in the lower part of a hopper so that the material containing separable matter is constrained to pass through the separator as it discharges from the hopper. The structure comprises a plurality of spaced apart rows of magnets 11, the several rows of magnets being intersected by transverse spaced apart metal strips 12. Together, the magnets 11 and strips 12 provide a plurality of magnetic elements which define a grate presenting a plurality of openings 13 for passage of the material therethrough.

The magnets 11 are preferably elongated in shape, and, in each row, are mounted in end to end alternately opposed relationship with like poles of adjacent magnets in facing relation. There is a metal strip 12 at each end of the rows of magnets and other strips 12 received between adjacent pairs of magnets. The like poles of adjacent magnets are thus separated by and abut a strip 12, each such strip being common to and extending across the several rows of magnets. The several strips 12 thus assume the character of pole pieces of alternate polarity, and are spaced apart a distance equal to the length of one magnet 11. The distance between the rows of magnets also being approximately equal to the length of one magnet, the openings 13 are substantially square or equal sided.

Each magnet 11 has a longitudinal opening 14 therethrough (Fig. 2) which, with the magnets aligned in a row, cooperates to define a longitudinal passage to receive a tie bolt 15. Corresponding openings in the pole pieces 12 permit passage of the bolts 15 therethrough, the opposite ends of the bolts projecting through and beyond the end pieces 12 and receiving nuts 16. Tightening of the nuts 16 upon the bolts efiects a clamping engagement between the magnets 11 and pieces 12, joining the parts into a unitary rigid structure. The magnets 11 are of such shape, or so positioned upon the tie bolts 15, that the upper surfaces thereof will extend generally downward in the direction of travel of the material, thereby reducing turbulence in the material flow and avoiding the formation of lands upon which material might collect.

ture to preclude the possibility of a metal particle descending through an opening 13 at a point where it will be equally attracted by the opposite pole pieces and associated magnets and hence not be deposited on any. This means is in the form of an assembly of small diameter round rods or wires 17 extending across the openings 13 centrally thereof and in transverse relation to the rows of magnets 11. The rods 17 are supported by side plates 18 of non-magnetic material, arranged alongside the outer rows of magnets 11 and in embracing relation to the ends of the pieces 12 to which the plates are structurally connected. Being supported in elevated relation to the grate the rods 17 are sufiiciently far removed from the magnetic field that they are not substantially aflected thereby whether they be of magnetic or non-magnetic material. So that there may be no appreciable restriction to flow the rods are positioned ..so.

that the diagonal distance between each rod and an adjacent pole piece is approximately equal to the distance between :the piecess Accordingly, metal particles tending to descend mid-' way-between "opposite. pole pieces -12 ofthe openings -13 are deflected by" the rods 17 into the magnetic -.fieldof one or another of such 'piecess Supplementalideflecting plates 19*inay besecured-tothe separating unit. to insure that all materialwill pass through the.=separator rather than 1 around the edges thereof intermediate .the separatorandthe material discharge duct. in which the separator ispositioned.

From the above:description itfiwill be aonarent that" theresis: wthus provided a devicef the character 'de' scribed :possessing the -particular rfea-tures---of'-*advantage' before enumerated as desirable, but which obviously "is susceptible of 1 modification in 'its -form, proportions, detail construction and "arrangement of= parts' without -departing from the principld in'volved or sacrificin'g 'any'of its advantages.

While-in order to' cornply --with "the *statute the driven tion has been described in-la'nguage more or less specific as to structuralfeatures-it is to'be understood' that'the invention :is' not limited' to" the specific features" shown; bu-tthat-the means and construction herein disclosed com prise but one of 'se-veralmodesof putting the invention into effect.-

Having this described' my invention, I claim:

1a A- grid' type-magneticseparator, including a plurality ofspaced-apart rows of magnets; the magnets of-each row =bein'g arranged in alternately opposed relationship with -lik'e epol'espfadjacent magnets in'tacing relation,- metal strips'having-the character of pole piecesextendin'g transversely across the several rows of magnets to acquire an inducedr'magnetism;"there being a strip at each 'end of the rowsofmagnets and- "one' between 'the opposing faces of each pair of magnets; and means for cla'mping the mag-' nets: and transverse stripsinto 'a 'unitary'assembly "to define a-grate structure;

2. A grid type magnetic'separator' according to clairn' 1, characterized in that'said clamping means is in the form of a plurality of tie rods,"one for each row of magnets, each extending .ilongitudintllY-through'a respective row of magnets'and associated transverse strips.

3. A grid type magnetic'separator, including a pluralityof spaced apart. rows of magnets and a pluralityjof spaced apart metallic strips having induced magnetism extending. across the several rows, the magnets of each row being in alternately opp'osed relationship with'like poles of adjacent magnets in facing relation and said strips being. interposed between the opposing faces of ad jacent magnets to assume the character of pole pieces.

4. A 'grid type magnetic separator, including ,a plurality of spaced apart rows of magnets, the magnets of each row being arranged in .alte'r'nately'. opposed relationship withlike poles of adjacent magnets'iin facin'g relation. metal strips extending transverselyjacross said rows-of magnets and received between opposing pairs ofinagnets in each row to be inductively magnetized thereby other transverse strips at the opposite ends-of the.rows-'of magnets, tie rods extendirigbetween said other. strips and passed longitudinally throughfthel rows of magnets and. interposed strips, said magnets being arrang d on .said tie'rods to present downwardly'sloping :surfaceshto the material passed throughfthe separator.

5..A.'grid type magnetic. separator, including ,a plurality of, spaced-apart-rows of magnetsand aplurality of spaced apart metallic.stripSextendingacross the' sev-. eral rows at right angles thereto,-the're being. strips at the ends of said rows and other strips intermediate adjacent pairs of magnets,. the-magnetsx o .each lrowflbein'g arr. ranged in alternately opposed v relationship. ,with. like. poles 4: other strips therebetween, and meansforuniting said magnets and strips into an assembly defining a grate structure presenting a plurality of material passing openings each bounded by magnets and by strips of induced magnetism and alternate polarity.

6. A grid type magnetic separator, including a plurality of spaced apart rows of" magnets, the magnets of each row being located in alternat'elyiopposed relation to one another, a plurality of spaced apart metallic strips so arranged wirhi respect to the'magnets to-b'einduerively magnetized thereby and extendingatright angles 'to 'th magnets across the several rows, said magnets and said strips cooperating to define a. grate: structure .=presenting a plurality of rows of material passing ,opcnings, and defleeting means common 'to'res ectivero'ws openings for precluding passage of material through said openings centrally thereof at points of equalized magnetic attraction.

7."A.grid type "magnetic separator, including a -plurality ofspaced'apart'rows'of magnets and 'a plurality .of spacedapartmetallic'strips ofin'duce'd magnetism at right angles to said magnets'and extending across the several rows thereoflth magnetspf each row being in alternatively opposed relation hipwi'th like poles of adjacent 'magnets'imfacing relation .and said strips being interposed between the op osing ta'ces o adjacent magnetsto-assunle the "character"'of polefpic'ce's of alternating polarity {said magnets and strips cooperating to definea grate structurepresenting a plurality ofmate'rial passing openingshavinglrnaglletic boundaries; and deflecting 'meansoverlying"said "o enings to preclude the passage of material theretltroug'h 'afpoints'where" the magnetic attraction of said boundaries is equalized.

8. A -grid' type magnetic" separator," including a 'pluralit'y of 'spacedaparrrows'nf magnets, the magnets of each row'being "arranged" "in alternately o posed relationship :withlike poles- 'of adjacent magnets: in facing relation-metal strips extending'transversely across the several rows ofmagnets at the opposite ends'th'r'eof and other metal strips extending in spaced apart relation to each 'other and'to 'the' tint strips transversely across the rows of-magnetsythe'first'said strips abutting the ends oftlte"rows of magnets and "said otherstrlps being'received between the opposing faces of adjace'nfpairsof magnets, said"'strips" acquiring from said magnets an induced "magnetism of' alternate polarity, means interconnecting said magnets"'and"'strips' to define a grate structure presenting a plurality of material'passing openings haying magnetic boundaries; a series of small diameter non-magnetic deflector rods extending in' "overlying relation to said openings to 'deflectmetallic matter tending to pass-centrally throu'glr'theopenings toward one or anotherof' the magnetic boundaries; and means for fixing said deflector rods with respect'to thegrate'strttcturc;

9. A grid type magneticseparatoraccording to claim'S, characterized in that said last named-"meansmomprises nonmagnetic side-plates at "the 'ends of -said metal strips and parallel to-the'rows (if-magnets; said-defiectorrods being supported between said plates in transverse relationto the rows' of magnets'andin intermediatevertically spaced relationdo 'said metal'strips.

10."-A- grid type magnetic separator according to claim 8, characterized in that the diagonal 'distancevbtween each' detlector-rod"and themetalstripson either side thereof is I approximately equal to 'the'distance between said strips.

11 A grid formed bf-a plurality ofspaccd magnetic bars; spacers extending'between the 'bars to form a grid, said spacers being "alined in rows transversely of i the bars, said spacers being permanent'='m-agnets," I the 'arrangement' being "such zthatatheends ofimagnets engaging I each'bamisiofithelsamepolarity.

of adjacentmagnets'intacing relation and receivingsaid 12. A magnetic separator grate a comprisingwa nonmagnetic substantially: rectangular frame a series of -rn'agnetic parallel cross bars including two terminal-bars aaaaos positioned in said frame in spaced relationship, said terminal bars located adjacent said frame and extending along opposite sides thereof, permanent magnets located intermediate said magnetic parallel cross bars in contact therewith in such manner that like poles of adjacent magnets lie next to and on opposite sides of each of said cross bars.

13. A magnetic separator grate comprising a plurality of spaced magnetic parallel bars, permanent magnets located intermediate said spaced magnetic parallel bars in such manner that like poles of adjacent magnets lie in contacting relation with and on opposite sides of each of said magnetic bars.

References Cited in the file of this patent UNITED STATES PATENTS 189,046 King Apr. 3, 1877 354,853 Bell Dec. 21, 1886 570,496 Osborn Nov. 3, 1896 2,293,664 Roberts Aug. 18, 1942 2,456,136 Manegold Dec. 14, 1948 FOREIGN PATENTS 570,515 Great Britain July 10, 1945 OTHER REFERENCES American Miller & Processor, October 1949, pages 68 and 83. 

